(i) Technical Field
The present invention relates to a developing device and an image forming apparatus.
(ii) Related Art
In a developing device in which developer containing toner serving as an image forming material and carriers serving as a transport medium for the toner is supplied to a bearing member for development while being agitated and transported by an agitating member, toner is supplied according to the toner concentration. In a structure using a toner concentration sensor to detect the toner concentration, when the amount of toner consumed by development increases and the transport amount (transport speed) of developer transported per unit time by the agitating member exceeds a reference speed, the amount of developer around the toner concentration sensor sometimes increases. In this case, the difference between the supply amount and the required amount of toner increases, and this may hinder supply of required toner.